High molecular weight coupled block copolymer compositions

Abstract

High molecular weight coupled block copolymer composition comprising (a) a linear diblock copolymer (I) represented by the general formula (A-B), having a peak apparent molecular weight of from 200,000 to 300,000, (b) a linear di-armed block copolymer (II), represented by the general formula (A-B) 2 X, (c) a tri-armed block copolymer (III), represented by the formula (A-B) 3 X, (d) a more than tri-armed block copolymer (IV), represented by the formula (A-B) n>3 X, (e) side polymeric structures (SPS) having a peak apparent molecular weight below the linear diblock copolymer (I), wherein A represents a block of predominantly poly(monovinyl aromatic hydrocarbon) and wherein the poly(monovinyl aromatic hydrocarbon) content is in the range of from 20 to 35 wt %; wherein B represents a block of predominantly poly(conjugated diene); wherein X is the residue of a trifunctional and/or tetrafunctional coupling agent; wherein the block copolymer composition has a weight average molecular weight M w in the range of from 450,000 to 800,000, and wherein the relative amounts of block copolymers corresponds to: I is from 5 to 15 wt %; II and III together are from 70 to 90 wt %, wherein III is above 10 wt %; IV is below 10 wt % and SPS is less than 10 wt % respectively, relative to the weight of the total block copolymer composition, in which the respective components add up to 100%.

1 . High molecular weight coupled block copolymer composition comprising
 (a) a linear diblock copolymer (I) represented by the general formula (A-B), having a peak apparent molecular weight of from 200,000 to 300,000,   (b) a linear di-armed block copolymer (II), represented by the general formula (A-B) 2 X,   (c) a tri-armed block copolymer (III), represented by the formula (A-B) 3 X,   (d) a more than tri-armed block copolymer (IV), represented by the formula (A-B) n>3 X,   (e) side polymeric structures (SPS) having a peak apparent molecular weight below the linear diblock copolymer (I),   wherein A represents a block of predominantly poly(monovinyl aromatic hydrocarbon) and wherein the poly(monovinyl aromatic hydrocarbon) content is in the range of from 20 to 35 wt %; wherein B represents a block of predominantly poly(conjugated diene); wherein X is the residue of a trifunctional and/or tetrafunctional coupling agent; wherein the block copolymer composition has a weight average molecular weight Mw in the range of from 450,000 to 800,000, and wherein the relative amounts of block copolymers corresponds to: I is from 5 to 15 wt %; II and III together are from 70 to 90 wt %, wherein III is above 10 wt %; IV is below 10 wt % and SPS is less than 10 wt % respectively, relative to the weight of the total block copolymer composition, in which the respective components add up to 100%.   
     
     
         2 . High molecular weight coupled block copolymer compositions according to  claim 1 , having a weight average molecular weight in the range of from 450,000 to 600,000, while the poly(monovinyl aromatic hydrocarbon) content is in the range of from 28 to 32 wt %. 
     
     
         3 . High molecular weight coupled block copolymer compositions according to  claim 1 , which comprise: (a) a linear diblock copolymer (I) represented by the general formula (A-B), having a peak apparent molecular weight of from 200,000 to 275,000, and wherein (II), (III) and (TV) have a peak apparent molecular weight of twice, three times, respectively more than three times said peak apparent molecular weight value of (A-B). 
     
     
         4 . High molecular weight coupled block copolymer compositions according to  claim 1 , wherein the monovinyl aromatic hydrocarbon is pure styrene and the conjugated diene is butadiene, isoprene or mixtures thereof. 
     
     
         5 . High molecular weight coupled block copolymer compositions according to  claim 1 , wherein the poly(conjugated diene) blocks have been hydrogenated up to a degree of at least 80%. 
     
     
         6 . High molecular weight coupled block copolymer compositions according to the  claim 5  wherein the ethylene content of the hydrogenated poly(conjugated diene) blocks is in the range from 50 to 65% by weight (based on the poly(conjugated diene) blocks). 
     
     
         7 . High molecular weight coupled block copolymer compositions according to  claim 1 , wherein the polymer blocks A have a true molecular weight in the range of from 30,000 to 70,000. 
     
     
         8 . Process for the manufacture of the high molecular weight coupled block copolymer compositions according to  claim 1 , comprising the preparation of a linear diblock copolymer (I) having a peak apparent molecular weight of from 200,000 to 300,000 and coupling the living diblock copolymer with a tetrafunctional and/or trifunctional silane coupling agent and where said coupling agent is used in an equivalent ratio of Si:Li (representing the active end in the initial block copolymer to be coupled) in the range of from 2:1 to 1:1. 
     
     
         9 . Process according to  claim 8  wherein the applied coupling agent is methyl tri(methoxy)silane. 
     
     
         10 . Shaped articles and gels derived from the high molecular weight coupled block copolymer compositions according to  claim 1 , mixed with extender oils, poly(olefins), poly(monovinyl aromatic) resins, hydrocarbon solvents, or mixtures thereof.